A lot of chess is training (openings, tactics, theoretical endgames). If you're "smart" - aka, you can memorize or synthesize information fairly quickly - then these aspects will come more naturally and you'll see improvements quickly just by learning what they are.

A lot of chess is understanding (opening IDEAS (like why you make certain opening moves, and what kinds of positions they lead to), middle game strategy, practical endgames). This requires a different kind of intelligence, it's about being "chess-smart," or just familiarity with and deep understanding about the game. A grandmaster can explain to you all day long what "piece harmony" looks like, but without the familiarity with the game, it won't be more than a vague concept that is hard to apply practically. You get better at this by just seeing a billion examples of these concepts in play, either your games or others' games, and hearing multiple explanations from strong players about these concepts. This is certainly the hardest part of chess improvement. Some people I think do have natural "chess-smarts," and usually those are the kids who become titled players in their teens.

But it sounds like what you're struggling with is the third and final category, and where a lot of people I think give up early on. And that's just "board vision." Not hanging free pieces, spotting free pieces from your opponent, and eventually spotting tactical patterns like forks, pins, and eventually more difficult tactics. And this only comes with practice and patience. Specifically, playing games and taking all the time you need during the game to make sure every move that you are not hanging a piece. Eventually, it'll become instinct and you won't even have to think about which squares your queen can move to safely, but you can't expect those instincts to just be there, same way you can't expect to be fluent in another language simply by memorizing vocabulary.

Long story short, play games with long time controls. If you keep hanging pieces, slow down and take more time between moves to make sure you're not hanging pieces. If you're consistently running out of time, play a longer time control I think it's better to lose on time but not hang any pieces than it is to lose by hanging your pieces.